摘要
以内燃机排气管系气体流动损失研究为背景,采用激光粒子图像测速技术对45°三分支管接头在流型6时的内部流场进行测量,获取了在不同流量比及气流马赫数工况下接头内部的流场数据。接头的支管段与主管段内径均为50mm,分支夹角的交界点处以及支管的转角处都为锐角边缘。通过对不同流量比q和马赫数Ma的工况进行测试,得到了气体在三分支流动中的试验数据。结合压力损失数据对比分析不同工况的速度场和流线图谱等流场特征,测试结果表明:流型6时,接头内的流场存在明显的流动收缩;气流的流动参数将影响和改变接头内的流场特性,其中随着支管与总管流量比的增大,接头内气流湍流区域扩大,压力损失增加;流出端马赫数对流场特征及压力损失也存在影响,Ma为0.13和0.31时,总压损失系数变化不大,当Ma增大到0.59时,总压损失系数大幅度增加。
The inner flow field in the 45°sharp-edged T type junction of the axial section was measured on the pressure loss of the exhaust system by Particle Image Velocimetry （PIV）.Char-acteristics of flow type 6 were obtained at different mass flow rate ratios and Mach numbera.The pipe area in each branch of the tested 45°junction remained constant,D =50mm.The axes in all branches were coplanar and the corners at the point of intersections between lateral branch and main branch were sharp edged.The experimental data were measured for the junction with vari-ous mass flow rate ratios （q =0,0.25,0.5,0.75 and 1）and Mach number in common branch （Ma=0.13,0.31 and 0.59）.Comparatively analysed the data of the velocity field and streamline pattern.Conclusion were drawn out that flow contraction occurred in downstream of the junc-tion.The feature of the flow field was related to the Mach number in common branch and the mass flow rate ratio between branch and duct in type 6.As the mass flow rate ratio of branch and duct increased,the turbulent region was enhanced and pressure loss enlarged.Mach number would also change the flow characteristics and pressure loss.The variation in the total pressure loss coefficient with Ma was fairly small in the range of 0.13 up to 0.31.However,along with the Mach number increased to 0.59,the coefficient increased more rapidly.
出处
《实验流体力学》
CAS
CSCD
北大核心
2014年第4期43-48,共6页
Journal of Experiments in Fluid Mechanics
